#include <iostream>
#include <vector>
#include <string>
#include <cstring>
#include <algorithm>
#include <map>
#include <climits>

using namespace std;
const int N=2005;
int getdis(int a,int b){
    int ans=a-b;
    return ans<0?-ans:ans;
}
int solve(string &s1,string &s2){
    int len=s1.size();
    sort(s1.begin(),s1.end());
    sort(s2.begin(),s2.end());
    int res=0;
    for(int i=0;i<len;i++){
        if(s1[i]!=s2[i]){
            res+=getdis(s1[i],s2[i]);
        }
    }
    return res;
}


int main(){
    int n;
    cin >> n;
    string s1,s2;
    cin >> s1>>s2;

    cout << solve(s1,s2)<<endl;


    return 0;
}